The invention relates generally to electrical connectors, and more particularly, to a connector that minimizes crosstalk among signal conductors in the connector, minimizes return loss in a pair of signal conductors in the connector, and minimizes alien cross talk from signal conductors in neighboring connectors.
In electrical systems, there is increasing concern for preserving signal integrity as signal speed and bandwidth increase. One source of signal degradation is crosstalk between multiple signal paths. In the case of an electrical connector carrying multiple signals, crosstalk occurs when signals conducted over a first signal path are partly transferred by inductive or capacitive coupling into a second signal path. The transferred signals produce crosstalk in the second path that degrades the signal routed over the second path.
For example, a typical industry standard type RJ-45 communication connector includes four pairs of conductors defining different signal paths. The RJ-45 plug design is dictated by industry standards and is inherently susceptible to crosstalk. In conventional RJ-45 plug and jack connectors, all four pairs of conductors extend closely parallel to one another over a length of the connector body. One pair of conductors is also split around another conductor pair. Thus, signal crosstalk may be induced between and among different pairs of connector conductors. The amplitude of the crosstalk, or the degree of signal degradation, generally increases as the frequency increases. More crosstalk can be created by the contacts in the jack that interface with the contacts in the plug. As signal speed and density increase, alien crosstalk, or crosstalk between neighboring connectors must also be addressed in preserving signal integrity.
At least some RJ-45 jacks include features that are intended to suppress or compensate for crosstalk. The shortcomings that are inherent in jacks such as the RJ-45 can be expected to become more serious as system demands continue to increase. It would be desirable to develop a connector that is designed to minimize both internal crosstalk and alien crosstalk at the outset rather than to correct for crosstalk after the fact.
Another source of signal degradation is return loss resulting from signal reflections along the conductors. Return loss can originate from multiple sources such as variations in impedance among the various elements in the connector as well as along the signal path. Improving return loss performance has proven to be difficult.